The left ventricle is the large, muscular chamber of the heart that pumps blood out to the body. Congestive heart failure (CHF) is a condition in which the heart can't pump enough blood to the body's other organs. It is a complex multi-factorial disease which often begins after an index event such as a severe heart attack which produces an initial decline in pumping capacity of the heart. There are 800,000 people with end-stage CHF and only 2,200 hearts available for transplant each year, leaving a large number of people suffering from this disease. Most CHF patients endure long hospital stays and other medical complications. For people over age 65, it is the number one cause of death, with nearly 290,000 people dying from this disease each year.
Of the 800,000 people who suffer from end-stage heart failure, about 48,000 are suitable for bridge to transplant and 90,000 patients are suitable for destination therapy. Bridge to transplant refers to the use of ventricle assist devices (VADs) to sustain severe heart failure patients until a donor heart becomes available and they can receive a transplant. Destination therapy refers to the use of a left ventricular assist device for long-term therapy. Destination therapy has a larger market potential than the bridge to transplant, however there is only one FDA approved participant in this market.
After the initial decline in pumping capacity of the heart following heart failure, a variety of compensatory mechanisms are activated. The phenomenon of left ventricular remodeling, i.e. a geometrical change in the architecture of the left ventricle, followed by a change in the wall stress is considered the single most important cause for the worsening of these heart attack patients. These patients often drift from Class I to Class IV stage heart failure. Subsequently these patients are rendered helpless and immobile with no options for treatment other than maintenance therapies—and, if the patient is young enough, placement on a cardiac transplant waiting list.
One treatment for patients who suffer from either a myocardial infarction or CHF is the implantation of a direct cardiac compression device. Currently, a sternotomy is the preferred method of implantation of the cardiac compression device. Sternotomy is a type of surgical procedure in which a vertical inline incision is made along the sternum, after which the sternum itself is divided, or “cracked”. This procedure provides access to the heart for surgical procedures. Conventional direct cardiac compression devices, such as the Anstadt cup, require a sternotomy for implantation, which is a very painful procedure. Disadvantageously, sternotomies result in long recovery times and a high risk of infection. Further, there is a high risk of complications due to the lengthy surgery required for these unstable patients.
What is desired is a minimally invasive apparatus and associated implantation method adapted to permit the insertion of a cardiac assist device about the heart of a patient which can modulate the end diastolic volume of the left ventricle. End diastolic volume is the volume of blood in a ventricle at the end of filling or diastole. Diastole is the period of time when the heart fills with blood after systole, or contraction. Such an apparatus and method would be preferable over treatment with pharmacological therapies or expensive device therapies.
Current approaches to minimally invasive implantation of heart-assist devices of various types suffer the shortcoming of being relatively slow and difficult procedures, resulting in additional stress on the patient and reducing the likelihood of a favorable outcome. The present invention addresses this shortcoming.